Nephrology concerns the diagnosis and treatment of kidney diseases, including electrolyte disturbances and hypertension, and the care of those requiring renal replacement therapy, including dialysis and renal transplant patients. Many diseases affecting the kidney are systemic disorders not limited to the organ itself, and may require special treatment. Examples include acquired conditions such as systemic vasculitides (eg. ANCA vasculitis) and autoimmune diseases (eg lupus), as well as congenital or genetic conditions such as polycystic kidney disease.

A nephrologist is a physician who has been trained in the diagnosis and management of kidney disease, by regulating blood pressure, regulating electrolytes, balancing fluids in the body, and administering dialysis. Nephrologists treat many different kidney disorders including acid-base disorders, electrolyte disorders, nephrolithiasis (kidney stones), hypertension (high blood pressure), acute kidney disease and end-stage renal disease.